Rolling Shutter Effect Demonstrated

I got curious, tried something out, and it worked. I was wondering if panning with a moving object and forcing the use of the electronic shutter on the XT would give me a slanted background but a vertical subject, and it did indeed. If there's anyone not familiar with "rolling shutter," I'll try to define it quickly:

When a camera uses the electronic shutter, what it's doing is reading out the pixels from the top left to the bottom right, scanning line by line like an old cathode ray tube TV. So if you've got fast motion (subject OR camera), the image will "lean" one direction and slant, because by the time the sensor gets to scanning the bottom pixels on the sensor, things ain't exactly where they used to be. Instead of motion blur, like you'd get on a physical shutter, you get a crisp tilt.

So in this case, I was panning with the cyclist, and shot at 1/5000 (I think). Note the buildings leaning left, but the cyclist looking normal. He was still in the same spot during my 1/5000th of a second, start to finish, but the bottom of the buildings had moved over a few feet.

Great question... I assume that panning left, as I did, "stretches" the image laterally, while panning right would "compress" it. I'm not sure if the final result would look as tilted.

My brain is also telling me, in very vague terms, that panning left has the equivalent effect of using a slightly longer focal length, whereas panning right would be like using a slightly wider lens, since you'd be getting more width into the frame... but my brain may be full of it.

I've been thinking about this since my last question. I think the effect of panning with or against the scan will be to stretch and compress objects within the picture respectively (horizontally in this case). The direction in which vertical elements lean will reverse too.